Analysis of the Bedform Variation in a Meandering Erodible Channel Using the Model FLUVIAL-12

This study includes the investigation on flow characteristics and the resulting bedform variation due to the sediment transport during the time of maximum flood and the base runoff at the upper watershed of Han River. The analyses were performed applying the FLUVIAL-12 to the project site, in which the finite difference method was adopted to solve the continuity and momentum equations in 1-D unsteady flow, including the equations for the sediment transport. The stage-discharge relationship determined from precipitation of 8 hr. duration was used as input data for it. The modeling results show that for the well-developed meandering channel a triangular bedform develops at an intersection of two points: the end point of a straight reach and the initial point of a curved reach, while a trapezoidal bedform develops at the middle reach. It was attributed to the 'distance lag' resulting from the difference between the centerline of the theoretical flow and the thalweg of the real flow. Even through the model used in this study could not simulate completely the dynamics of flow and the resulting bedform variation occurring in nature, it appears that the useful information could be obtained from it in case of engineering purpose, in which the simple and approximate but fart estimations are required frequently.